1. Field of the Invention
This invention relates to a method of using a water based primer on masonry, particularly concrete, to improve the bond of silicone water based coatings and sealants, and the masonry so protected.
2. Background Information
Findley and Weyenberg disclosed in U.S. Pat. No. 3,294,725, issued Dec. 27, 1966, a method of polymerizing siloxanes and silcarbanes in emulsion by using a surface active sulfonic acid catalyst. Johnson et al described in U.S. Pat. No. 4,221,688, issued Sep. 9, 1980 means for combining such emulsion polymers with an organic tin compound and silica to make emulsions which can be used as coatings.
In U.S. Pat. No. 4,273,813, issued Jun. 16, 1981, Meddaugh describes a method of providing waterproof coating for masonry walls.
A silicone elastomeric emulsion having improved shelf life is taught in U.S. Pat. No. 4,427,811. The emulsion is prepared by mixing an anionically stabilized, hydroxyl endblocked polydiorganosiloxane, colloidal silica, and an alkyl tin salt, ages for at least two weeks at room temperature, then adds filler other than colloidal silica.
An aqueous silicone elastomeric emulsion which was useful as a caulking material was described by Schoenherr in U.S. Pat. No. 4,618,642, issued Oct. 21, 1986.
Another method of producing an emulsion of crosslinked polydiorganosiloxane which yields an elastomer upon removal of the water emulsifies a mixture of hydroxyl endblocked polydiorganosiloxane, alkoxy silicone compound, anionic emulsifying agent, and water, then admixes surface active anionic catalyst. Maintaining at a pH of less that 5 at room temperature allows the ingredients to act and raise the molecular weight of the polydiorganosiloxane and to crosslink the polymer.